Or they could go with niche products that Pakistani officials have no clue about. SMS messages as you said, for example, that use some traditional encryption/decryption methods not involving software. Wait... wait... there's one even better - pidgeons! ;)

This is so idiotic move by Pakistani ISI that I could not hold myself but to comment. I have over 20 years of experience by working in intelligence/counterintelligence and this is outright stupid. Pakistani ISI is saying: "We can no crack BBSMS, kill it". Now blackberry owner having shady activities and suspect that it may be monitored know: "I have to switch". "Others are not banned so I cannot use their services either". And if they are serious about hiding ... they WILL find software providers who will give to them OneTimePad protection services for regular SMS (you cannot kill regular sms in whole country, or why not stupidity is boundless :). Result: goodbye monitoring forever. Even hyper intelligent aliens can't help then let alone USA as ally.